We are going for outpatient surgery next week to remove our daughter's. The ENT stated we could wait for a few weeks if we wanted, but we are anxious to have it removed. He reports he has completed numerous surgeries like these and recovery will not be bad for her age and region of growth. It will be a personal decision of yours and your family once meeting with the appropriate doctor. Good luck!
No, do not do surgery immediately, unless you know the doctor has experience with this condition. Having the right doctor is huge, as you don't want to put your child through unnecessary pain. Cystic Hygroma is NOT cancerous and won't become cancerous. All it is, is a malformation of the lymphatic system. Getting a second opinion is a good next step. I would ask about sclerotherpy as a first treatment, instead of jumping into surgery. It's much less invasive and has an easier recovery. if you have any other questions, feel free to ask.
All the research we have found states cystic hygroma is not cancerous, however can become disfiguring as the child gets older. We follow up with the ENT tom after our daughter's CT scan. Will post their suggestions when I can.